U.S. patent number 10,955,772 [Application Number 16/824,734] was granted by the patent office on 2021-03-23 for belt positioning structure, belt and roller unit, and image forming apparatus.
This patent grant is currently assigned to TOSHIBA TEC KABUSHIKI KAISHA. The grantee listed for this patent is TOSHIBA TEC KABUSHIKI KAISHA. Invention is credited to Takehiro Meguro.
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United States Patent |
10,955,772 |
Meguro |
March 23, 2021 |
Belt positioning structure, belt and roller unit, and image forming
apparatus
Abstract
According to one embodiment, there is provided a belt
positioning structure including a belt roller, a belt, a
projection, and a first rotating body. The belt roller is rotatable
about a roller axis. The belt is wound around the belt roller. The
projection is provided so as to protrude from an inner peripheral
surface of the belt. The first rotating body regulates the
projection from moving in a first direction approaching the belt
roller along the roller axis. The first rotating body is rotatable
around an axis. At least a portion of an outer peripheral surface
of the first rotating body faces a side surface of the projection
on the first direction side.
Inventors: |
Meguro; Takehiro (Hiratsuka
Kanagawa, JP) |
Applicant: |
Name |
City |
State |
Country |
Type |
TOSHIBA TEC KABUSHIKI KAISHA |
Tokyo |
N/A |
JP |
|
|
Assignee: |
TOSHIBA TEC KABUSHIKI KAISHA
(Tokyo, JP)
|
Family
ID: |
1000004738167 |
Appl.
No.: |
16/824,734 |
Filed: |
March 20, 2020 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G03G
15/1615 (20130101); G03G 15/1625 (20130101) |
Current International
Class: |
G03G
15/16 (20060101) |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Hyder; G. M. A
Attorney, Agent or Firm: Amin, Turocy & Watson, LLP
Claims
What is claimed is:
1. A belt positioning structure, comprising: a belt roller
configured to rotate about a roller axis; an endless belt
configured to be wound around the belt roller; a projection
provided so as to protrude from an inner peripheral surface of the
endless belt; a first rotating body configured to regulate the
projection from moving in a first direction approaching the belt
roller along the roller axis, wherein the first rotating body is
rotatable around an axis, and at least a portion of an outer
peripheral surface of the first rotating body faces a side surface
of the projection on the first direction side; and a second
rotating body configured to regulate the endless belt from moving
in a direction away from the roller axis, wherein the second
rotating body is rotatable around an axis, and at least a portion
of an outer peripheral surface of the second rotating body faces an
outer peripheral surface of the endless belt, and wherein a flange
part protruding radially outward of the second rotating body is
provided on the outer peripheral surface of the second rotating
body, and at least a portion of a side surface of the flange part
on the first direction side faces an end surface of the endless
belt on a second direction side opposite to the first
direction.
2. The structure according to claim 1, wherein the outer peripheral
surface of the first rotating body includes a first region that
regulates the projection from moving in the first direction and a
second region that regulates the endless belt from moving in a
direction approaching the roller axis, at least a portion of the
first region faces the side surface of the projection on the first
direction side, and at least a portion of the second region faces
the inner peripheral surface of the endless belt.
3. The structure according to claim 1, wherein the outer peripheral
surface of the first rotating body includes a first region that
regulates the projection from moving in the first direction and a
second region that regulates the projection from moving in a
direction approaching the roller axis, at least a portion of the
first region faces the side surface of the projection on the first
direction side, and at least a portion of the second region faces
an inner peripheral surface of the projection.
4. A belt positioning structure, comprising: a belt roller
configured to rotate about a roller axis; an endless belt
configured to be wound around the belt roller; a projection
provided so as to protrude from an inner peripheral surface of the
endless belt; a first rotating body configured to regulate the
projection from moving in a first direction approaching the belt
roller along the roller axis, wherein the first rotating body is
rotatable around an axis, and at least a portion of an outer
peripheral surface of the first rotating body faces a side surface
of the projection on the first direction side; and a second
rotating body configured to regulate the endless belt from moving
in a direction away from the roller axis, wherein the second
rotating body is rotatable around an axis, and at least a portion
of an outer peripheral surface of the second rotating body faces an
outer peripheral surface of the endless belt, wherein the outer
peripheral surface of the second rotating body includes a third
region that regulates the endless belt from moving in a second
direction opposite to the first direction and a fourth region that
regulates the endless belt from moving in a direction away from the
roller axis, at least a portion of the third region faces an end
surface of the endless belt on the second direction side, and at
least a portion of the fourth region faces the outer peripheral
surface of the endless belt.
5. A belt positioning structure, comprising: a belt roller
configured to rotate about a roller axis; an endless belt
configured to be wound around the belt roller; a projection
provided so as to protrude from an inner peripheral surface of the
endless belt; a first rotating body configured to regulate the
projection from moving in a first direction approaching the belt
roller along the roller axis, wherein the first rotating body is
rotatable around an axis, and at least a portion of an outer
peripheral surface of the first rotating body faces a side surface
of the projection on the first direction side; a second rotating
body configured to regulate the endless belt from moving in a
direction away from the roller axis, wherein the second rotating
body is rotatable around an axis, and at least a portion of an
outer peripheral surface of the second rotating body faces an outer
peripheral surface of the endless belt; and an urging mechanism
configured to urge at least one of the first rotating body and the
second rotating body in a direction approaching the projection.
6. The structure according to claim 1, wherein the first rotating
body and the second rotating body are provided on an upstream side
in a running direction of the endless belt.
7. The structure according to claim 4, wherein the outer peripheral
surface of the first rotating body includes a first region that
regulates the projection from moving in the first direction and a
second region that regulates the endless belt from moving in a
direction approaching the roller axis, at least a portion of the
first region faces the side surface of the projection on the first
direction side, and at least a portion of the second region faces
the inner peripheral surface of the endless belt.
8. The structure according to claim 4, wherein the outer peripheral
surface of the first rotating body includes a first region that
regulates the projection from moving in the first direction and a
second region that regulates the projection from moving in a
direction approaching the roller axis, at least a portion of the
first region faces the side surface of the projection on the first
direction side, and at least a portion of the second region faces
an inner peripheral surface of the projection.
9. The structure according to claim 4, wherein the first rotating
body and the second rotating body are provided on an upstream side
in a running direction of the endless belt.
10. The structure according to claim 5, wherein the outer
peripheral surface of the first rotating body includes a first
region that regulates the projection from moving in the first
direction and a second region that regulates the endless belt from
moving in a direction approaching the roller axis, at least a
portion of the first region faces the side surface of the
projection on the first direction side, and at least a portion of
the second region faces the inner peripheral surface of the endless
belt.
11. The structure according to claim 5, wherein the outer
peripheral surface of the first rotating body includes a first
region that regulates the projection from moving in the first
direction and a second region that regulates the projection from
moving in a direction approaching the roller axis, at least a
portion of the first region faces the side surface of the
projection on the first direction side, and at least a portion of
the second region faces an inner peripheral surface of the
projection.
12. The structure according to claim 5, wherein the first rotating
body and the second rotating body are provided on an upstream side
in a running direction of the endless belt.
Description
FIELD
Embodiments described herein relate generally to a belt positioning
structure, a belt and roller unit, and an image forming
apparatus.
BACKGROUND
As an image forming apparatus, there are a multi-function
peripheral (MFP) which is a multifunction machine, a printer, a
copying machine, and the like. The image forming apparatus
transfers a toner image to an endless transfer belt and transfers
the toner image to a recording medium such as a paper sheet.
The transfer belt may include a rib on an inner peripheral surface
thereof for preventing the belt from being deviated. A roller
around which the transfer belt is wound may include a regulating
plate on which the rib can abut. The regulating plate forms an
inclined surface on which the rib can abut. The regulating plate
returns the rib and the transfer belt to a normal position by the
inclined surface. For that reason, skewing of the transfer belt can
be suppressed.
When the transfer belt is skewed greatly, a deviating force of the
belt may exceed a regulation force for returning the rib to the
normal position by the inclined surface of the regulating plate. In
this case, the rib rides up on the inclined surface of the
regulating plate. When the rib rides over the inclined surface up
to a cylindrical belt winding surface, the rib and the transfer
belt may come off from their normal positions and fall off.
DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic view of an example of an overall
configuration of an image forming apparatus according to an
embodiment;
FIG. 2 is a plan view of a secondary transfer backup roller, an
intermediate transfer belt, and a positioning projection in the
embodiment;
FIG. 3 is a front view of a first example of a belt positioning
structure;
FIG. 4 is a cross-sectional view of the first example of the belt
positioning structure;
FIG. 5 is a cross-sectional view of a second example of the belt
positioning structure;
FIG. 6 is a cross-sectional view of a third example of the belt
positioning structure;
FIG. 7 is a cross-sectional view of a fourth example of the belt
positioning structure;
FIG. 8 is a schematic view illustrating an example of installation
positions of a first rotating body and a second rotating body in
the embodiment; and
FIG. 9 is a plan view illustrating the example of the installation
positions of the first rotating body and the second rotating
body.
DETAILED DESCRIPTION
In general, according to one embodiment, there is provided a belt
positioning structure including a belt roller, a belt, a
projection, and a first rotating body. The belt roller is rotatable
about a roller axis. The belt is wound around the belt roller. The
projection is provided so as to protrude from an inner peripheral
surface of the belt. The first rotating body regulates the
projection from moving in a first direction approaching the belt
roller along the roller axis. The first rotating body is rotatable
around an axis. At least a portion of an outer peripheral surface
of the first rotating body faces a side surface of the projection
on the first direction side.
Hereinafter, a belt positioning structure, a belt and roller unit,
and an image forming apparatus according to an embodiment will be
described with reference to the accompanying drawings. In the
respective drawings, the same components are denoted by the same
reference numerals. In each drawing, the size and shape of each
member may be exaggerated or simplified for easy viewing.
As illustrated in FIG. 1, an image forming apparatus 1 is, for
example, a multi-function peripheral (MFP) which is a multifunction
machine, a printer, a copying machine, and the like. Hereinafter, a
case where the image forming apparatus 1 is the MFP will be
described as an example.
A configuration of the image forming apparatus 1 is not
particularly limited. For example, the image forming apparatus 1
includes a main body 11. On the upper part of the main body 11, a
document table 12 including transparent glass is provided. An
automatic document feeder (ADF) 13 is provided on the document
table 12. On the upper part of the main body 11, an operation unit
14 is provided. The operation unit 14 includes an operation panel
14a including various keys and a touch panel type operation and
display unit 14b.
A scanner unit 15 is provided below the ADF 13. The scanner unit 15
reads a document sent by the ADF 13 or a document placed on the
document table 12. The scanner unit 15 generates image data of the
document. For example, the scanner unit 15 includes an image sensor
16. For example, the image sensor 16 may be a contact type image
sensor. The image sensor 16 moves along the document table 12 when
reading an image of the document placed on the document table
12.
A sheet feed cassette 18A (18B) includes a sheet feed mechanism 19A
(19B). The expression "The sheet feed cassette 18A (18B) includes
the sheet feed mechanism 19A (19B)" means that both the sheet feed
cassette 18A includes the sheet feed mechanism 19A, and the sheet
feed cassette 18B includes the sheet feed mechanism 19B. The same
applies to the following description.
The sheet feed mechanism 19A (19B) picks up sheets (sheet-shaped
recording media such as paper sheets) P one by one from the sheet
feed cassette 18A (18B) and sends the sheets to a conveyance path
of the sheet P. For example, the sheet feed mechanism 19A (19B) may
include a pickup roller, a separation roller, and a sheet feed
roller.
A manual sheet feed unit 18C includes a manual sheet feed mechanism
19C. The manual sheet feed mechanism 19C picks up the sheets P one
by one from the manual sheet feed unit 18C and sends the sheets P
to the conveyance path.
A printer unit (image forming unit) 17 forms an image on the sheet
P based on image data read by the scanner unit 15 or image data
generated by a personal computer or the like. The printer unit 17
is, for example, a tandem-type color printer.
The printer unit 17 includes image forming parts 22Y, 22M, 22C, and
22K for colors of yellow (Y), magenta (M), cyan (C), and black (K)
corresponding to color separation components of a color image, an
exposure device 23, and an intermediate transfer belt 24.
A configuration of the printer unit 17 is not limited to this, and
the printer unit 17 may include two or three image forming parts,
or the printer unit 17 may include five or more image forming
parts.
Although not illustrated, the exposure device 23 includes a light
source, a polygon mirror, an f-0 lens, a reflection mirror, and the
like. The exposure device 23 irradiates a surface of a
photoreceptor drum of each of the image forming parts 22Y, 22M,
22C, and 22K with exposure light, based on the image data.
The configurations of the image forming parts 22Y, 22M, 22C, and
22K are the same as each other except that a color of a toner is
different. As the toner, any of a normal color toner and a
decolorable toner may be used. Here, the decolorable toner is a
toner that becomes transparent when heated at a predetermined
temperature or higher. The image forming apparatus 1 may be the
image forming apparatus 1 that can use the decolorable toner, or
may be the image forming apparatus 1 that cannot use the
decolorable toner.
The intermediate transfer belt 24 is an endless belt. The
intermediate transfer belt 24 is wound around a secondary transfer
backup roller 32, a cleaning backup roller 33, and a tension
roller. In the embodiment, when the secondary transfer backup
roller 32 is driven to rotate, the intermediate transfer belt 24
runs around (rotates). An arrow R in the figure indicates a driving
direction (rotation direction) of the secondary transfer backup
roller 32.
Around the intermediate transfer belt 24, the image forming parts
22Y, 22M, 22C, and 22K, a secondary transfer roller 37, and a belt
cleaning mechanism 38 are disposed. A plurality of primary transfer
rollers 36 are disposed on the inner peripheral side of the
intermediate transfer belt 24 so as to face the image forming parts
22Y, 22M, 22C, and 22K.
The printer unit 17 of the embodiment includes a belt and roller
unit 31 that is detachable (replaceable) from the main body of the
printer unit 17. The belt and roller unit 31 is configured to
include the intermediate transfer belt 24, the secondary transfer
backup roller 32, the cleaning backup roller 33, the tension roller
34, and the plurality of primary transfer rollers 36.
Hereinafter, a configuration common to the image forming parts 22Y,
22M, 22C, and 22K will be described using the image forming part
22K as an example.
The image forming part 22K includes a photoreceptor 26K, a charger
27K, a developing device 28K, and a cleaner 29K.
The photoreceptor 26K is formed in a drum shape. An electrostatic
latent image such as a character or an image is formed on the
surface of the photoreceptor 26K by exposure light LK. The charger
27K charges the surface of the photoreceptor 26K. The developing
device 28K supplies a toner to the surface of the photoreceptor 26K
to develop the electrostatic latent image. The cleaner 29K cleans
the surface of the photoreceptor 26K.
The primary transfer roller 36 of the image forming part 22K forms
a primary transfer nip by sandwiching the intermediate transfer
belt 24 between the primary transfer roller 36 and the
photoreceptor 26K. A power source (not illustrated) is connected to
the primary transfer roller 36. At least one of a predetermined
direct current (DC) voltage and a predetermined alternating current
(AC) voltage is applied to the primary transfer roller 36.
The secondary transfer roller 37 forms a secondary transfer nip by
sandwiching the intermediate transfer belt 24 between the secondary
transfer roller 37 and the secondary transfer backup roller 32. A
power source (not illustrated) is connected to the secondary
transfer roller 37, similarly to the primary transfer roller 36. At
least one of a predetermined DC voltage and a predetermined AC
voltage is applied to the secondary transfer roller 37.
The transfer in the image forming apparatus 1 includes a first
transfer step and a second transfer step. In the first transfer
step, the toner images formed on the photoreceptors 26K of the
image forming parts 22Y, 22M, 22C, and 22K are transferred to the
intermediate transfer belt 24. In the second transfer step, the
toner images transferred to the intermediate transfer belt 24 are
transferred (printed) to the sheet P which is a recording
medium.
The belt cleaning mechanism 38 includes a cleaning brush and a
cleaning blade (reference numerals thereof are omitted) disposed so
as to abut on the intermediate transfer belt 24. A waste toner
transport hose (not illustrated) extends from the belt cleaning
mechanism 38 and is connected to a waste toner container (not
illustrated).
A supply unit 41 is disposed above the image forming parts 22Y,
22M, 22C, and 22K. The supply unit 41 supplies the toner to each of
the image forming parts 22Y, 22M, 22C, and 22K. The supply unit 41
includes toner cartridges 42Y, 42M, 42C, and 42K. The toner
cartridges 42Y, 42M, 42C, and 42K contain yellow, magenta, cyan,
and black toners, respectively.
Each of the toner cartridges 42Y, 42M, 42C, and 42K is provided
with a marking portion (not illustrated) that allows a main control
unit 53, which will be described later, to detect a type of toner
contained in each of the toner cartridges. The marking portion
includes at least information on colors of the toners of the toner
cartridges 42Y, 42M, 42C, and 42K and information for identifying
whether the toner is the normal toner or the decolorable toner.
A replenishment path (not illustrated) is provided between each of
the toner cartridges 42Y, 42M, 42C, and 42K and the corresponding
developing device. The toner is supplied from each of the toner
cartridges 42Y, 42M, 42C, and 42K to the corresponding developing
device via the replenishment path.
Sheet feed rollers 45A and registration rollers 46 are provided on
a conveyance path from the sheet feed cassette 18A to the secondary
transfer roller 37. The sheet feed rollers 45A convey the sheet P
picked up from the sheet feed cassette 18A by the sheet feed
mechanism 19A. The registration rollers 46 adjust a position of a
leading end of the sheet P fed from the sheet feed rollers 45A at
an abutment position on each other.
The registration rollers 46 convey the sheet P to the secondary
transfer nip.
Sheet feed rollers 45B are provided on a conveyance path from the
sheet feed cassette 18B to the sheet feed rollers 45A. The sheet
feed rollers 45B convey the sheet P picked up from the sheet feed
cassette 18B by the sheet feed mechanism 19B toward the sheet feed
rollers 45A.
A conveyance path is formed by a conveyance guide 48 between a
manual sheet feed mechanism 19C and the registration rollers 46.
The manual sheet feed mechanism 19C conveys the sheet P picked up
from a manual sheet feed unit 18C toward the conveyance guide 48.
The sheet P moving along the conveyance guide 48 reaches the
registration rollers 46.
A fixing unit (fixing device) 56 is disposed on a downstream side
(upper side in the figure) of the secondary transfer roller 37 in
the conveyance direction of the sheet P.
Conveyance rollers 50 are disposed on a downstream side (upper left
side in the figure) of the fixing unit 56 in the conveyance
direction of the sheet P. The conveyance rollers 50 discharge the
sheet P to a sheet discharge unit 51.
A reverse conveyance path 52 is disposed on an upstream side (right
side in the figure) of the fixing unit 56 in the conveyance
direction of the sheet P. In the reverse conveyance path 52, the
sheet P is reversed and guided toward the secondary transfer roller
37. The reverse conveyance path 52 is used when performing
double-sided printing.
The image forming apparatus 1 includes a main control unit 53 that
controls the entire image forming apparatus 1. The main control
unit 53 includes a central processing unit (CPU), a memory, and the
like.
The fixing unit 56 includes a fixing belt (belt), a pressurizing
roller (roller), and a heater (heating unit) (all are not
illustrated). The fixing belt and the pressurizing roller are
disposed side by side. The pressurizing roller is pressurized
toward the fixing belt side by a pressurizing unit (not
illustrated). A nip in which the sheet P is pinched is formed in a
portion against where the pressurizing roller and the fixing belt
are pressed.
The pressurizing roller is driven to rotate by a drive source such
as a motor (not illustrated). When the pressurizing roller is
driven to rotate, the driving force of the pressurizing roller is
transmitted to the fixing belt through the nip, and the fixing belt
is driven to rotate. The sheet P pinched in the nip is conveyed
downstream side in the conveyance direction by the rotation of the
pressurizing roller and the fixing belt. The fixing belt is heated
by the heater, and the toner image transferred to the sheet P is
fixed to the sheet P by the heat and pressure of the pressurizing
roller. The sheet P after image formation is discharged to the
sheet discharge unit 51.
During execution of a printing operation, the intermediate transfer
belt 24 may be skewed to run obliquely with respect to a normal
rotation direction, or may be deviated to one side in the axis
direction of the roller. Such an event may cause excessive input or
deformation of the intermediate transfer belt 24, which may lead to
breakage or dropout of the intermediate transfer belt 24. For that
reason, the image forming apparatus 1 includes a belt positioning
structure 30 for preventing the intermediate transfer belt 24 from
being deviated.
A belt positioning structure 30A, which is a first example of the
belt positioning structure 30, will be described with reference to
FIGS. 2 to 4.
As illustrated in FIGS. 3 and 4, the belt positioning structure 30A
includes the secondary transfer backup roller 32 (belt roller), the
intermediate transfer belt 24 (belt), a positioning projection 61
(projection), a first rotating body 71, and a second rotating body
72. In the figures, a reference numeral 32a indicates a support
shaft of the secondary transfer backup roller 32. A reference
symbol C indicates the center axis (roller axis) of the secondary
transfer backup roller 32. The secondary transfer backup roller 32
rotates about a center axis C.
As illustrated in FIGS. 2 to 4, the positioning projection 61 is
provided to protrude inward from an inner peripheral surface 24b of
the intermediate transfer belt 24. A projecting direction of the
positioning projection 61 is a thickness direction (downward in
FIGS. 3 and 4) of the intermediate transfer belt 24. The
positioning projection 61 is a rib (protrusion) extending along a
longitudinal direction of the intermediate transfer belt 24. For
example, a cross section orthogonal to a length direction of the
positioning projection 61 is rectangular. The positioning
projection 61 is formed continuously in a length direction of the
intermediate transfer belt 24. The positioning projection 61 is
preferably formed in an annular shape over the entire length of the
intermediate transfer belt 24.
For example, the positioning projection 61 is made of an elastic
member such as synthetic rubber separate from the intermediate
transfer belt 24. The positioning projection 61 is fixed to the
inner peripheral surface 24b of the intermediate transfer belt 24
by bonding or the like, and is capable of running around the
intermediate transfer belt 24 integrally. The positioning
projection 61 is disposed close to a side edge 24a of the
intermediate transfer belt 24.
In FIG. 3, a direction (direction toward the central side of the
roller axis) approaching the secondary transfer backup roller 32
along the roller axis (center axis C) of the secondary transfer
backup roller 32 is referred to as a "first direction D1". The
first direction D1 corresponds to a direction toward the left side
in FIG. 3. A direction (direction outside the roller axis) away
from the secondary transfer backup roller 32 along the roller axis
(center axis C), that is, the direction opposite to the first
direction D1, is referred to as a "second direction D2". The second
direction D2 corresponds to a direction toward the right side in
FIG. 3.
As illustrated in FIG. 4, the first rotating body 71 is formed in a
columnar shape. A reference numeral C1 is the center axis (rotating
body axis) of the first rotating body 71. A direction along a
center axis C1 is referred to as an axial direction. A recess 71b
is formed at the center of one end surface 71a (upper surface in
FIG. 4) in the axial direction of the first rotating body 71. At
the center of the bottom of the recess 71b, an insertion hole 71c
penetrating the first rotating body 71 in the axial direction is
formed.
The first rotating body 71 is rotatably supported by a shaft member
73. The shaft member 73 includes a head portion 73a and a support
shaft 73b extending from the head portion 73a. The support shaft
73b is inserted into the insertion hole 71c of the first rotating
body 71. With this configuration, the first rotating body 71 is
rotatable around the center axis C1. The head portion 73a is
accommodated in the recess 71b. For example, the first rotating
body 71 is made of an elastic member such as synthetic rubber.
The first rotating body 71 and the shaft member 73 are provided on
the inner peripheral surface 24b side of the intermediate transfer
belt 24. The first rotating body 71 is installed such that the end
face 71a faces the inner peripheral face 24b. The end face 71a of
the first rotating body 71 is preferably apart from the inner
peripheral face 24b. For example, the center axis C1 of the first
rotating body 71 is perpendicular to the intermediate transfer belt
24.
At least a portion of an outer peripheral surface 71d of the first
rotating body 71 faces an inner side surface 61a (left surface in
FIG. 4) which is the surface of the positioning projection 61 on
the first direction D1 side. The outer peripheral surface 71d of
the first rotating body 71 is preferably separated from the inner
side surface 61a. At a point of the outer peripheral surface 71d
closest to the inner side surface 61a, a direction of a tangent
line perpendicular to the center axis C1 is parallel to an
extending direction of the positioning projection 61.
When the intermediate transfer belt 24 and the positioning
projection 61 move in the first direction D1, the inner side
surface 61a of the positioning projection 61 abuts on the outer
peripheral surface 71d of the first rotating body 71. For that
reason, the movement of the intermediate transfer belt 24 in the
first direction D1 is regulated. With this configuration, deviation
of the intermediate transfer belt 24 can be suppressed. Therefore,
the reliability of the positioning of the intermediate transfer
belt 24 can be improved.
When the positioning projection 61 abuts on the outer peripheral
surface 71d of the first rotating body 71, the first rotating body
71 rotates around the center axis C1 as the intermediate transfer
belt 24 and the positioning projection 61 run. For that reason, the
frictional resistance between the positioning projection 61 and the
first rotating body 71 can be suppressed.
The second rotating body 72 is formed in a columnar shape. A
reference numeral C2 is the center axis (rotating body axis) of the
second rotating body 72. A direction along a center axis C2 is
referred to as the axial direction. At the central part of the
second rotating body 72, an insertion hole 72c penetrating the
second rotating body 72 in the axial direction is formed.
The second rotating body 72 is rotatably supported by a shaft
member 74. The shaft member 74 includes a head portion 74a and a
support shaft 74b extending from the head portion 74a. The support
shaft 74b is inserted into the insertion hole 72c of the second
rotating body 72. With this configuration, the second rotating body
72 can rotate around the center axis C2. The center axis C2 of the
second rotating body 72 is parallel to the center axis C (roller
axis) (see FIG. 3). For example, the second rotating body 72 is
made of an elastic member such as synthetic rubber.
The second rotating body 72 and the shaft member 74 are provided on
the outer peripheral surface 24c side of the intermediate transfer
belt 24. The second rotating body 72 is installed such that at
least a portion of the outer peripheral surface 72d faces the outer
peripheral surface 24c of the intermediate transfer belt 24. The
outer peripheral surface 72d of the second rotating body 72 is
preferably separated from the outer peripheral surface 24c. At a
point of the outer peripheral surface 72d closest to the outer
peripheral surface 24c, a direction of a tangent line perpendicular
to the center axis C2 is parallel to a running direction of the
intermediate transfer belt 24.
A distance a between the outer peripheral surface 72d of the second
rotating body 72 and the outer peripheral surface 24c of the
intermediate transfer belt 24 is preferably smaller than a
thickness A of the positioning projection 61. With this
configuration, it is possible to regulate that the positioning
projection 61 comes off the position where the positioning
projection 61 can be made to abut on the first rotating body
71.
At least a portion of the outer peripheral surface 72d of the
second rotating body 72 faces an outer peripheral surface 61c
(upper surface in FIG. 4) of the positioning projection 61 via the
intermediate transfer belt 24.
When the intermediate transfer belt 24 and the positioning
projection 61 move in a direction (upward in FIG. 4) away from the
center axis C (roller axis) (see FIG. 3), the outer peripheral
surface 24c of the intermediate transfer belt 24 abuts on the outer
peripheral surface 72d of the second rotating body 72. For that
reason, the outward movement (upward movement in FIG. 4) of the
intermediate transfer belt 24 is regulated. With this
configuration, it is possible to regulate that the positioning
projection 61 comes off the position where the positioning
projection 61 can be made to abut on the first rotating body 71.
Therefore, the reliability of the positioning of the intermediate
transfer belt 24 can be improved.
When the intermediate transfer belt 24 abuts on the outer
peripheral surface 72d of the second rotating body 72, the second
rotating body 72 rotates around the center axis C2 as the
intermediate transfer belt 24 runs. For that reason, the frictional
resistance between the intermediate transfer belt 24 and the second
rotating body 72 can be suppressed.
Next, a belt positioning structure 30B which is a second example of
the belt positioning structure 30 will be described with reference
to FIG. 5. The same components as those of the belt positioning
structure 30A illustrated in FIG. 4 are denoted by the same
reference numerals, and description thereof is omitted.
As illustrated in FIG. 5, the belt positioning structure 30B is
different from the belt positioning structure 30A illustrated in
FIG. 4 in that a first rotating body 171 and a second rotating body
172 are used instead of the first rotating body 71 and the second
rotating body 72.
An outer peripheral surface 171d of the first rotating body 171
includes a first region 171d1 and a second region 171d2. The first
region 171d1 is a region of the outer peripheral surface 171d
extending from one end 171a (first end 171a) in the axial direction
of the first rotating body 171 to the center in the axial
direction. The first region 171d1 is tapered such that the outer
diameter gradually increases from the first end 171a toward the
center in the axial direction. The second region 171d2 is a region
of the outer peripheral surface 171d extending from the other end
171b (second end 171b) in the axial direction of the first rotating
body 171 to the center in the axial direction. The second region
171d2 is tapered such that the outer diameter gradually increases
from the second end 171b toward the center in the axial
direction.
An insertion hole 171c penetrating in the axial direction is formed
in the first rotating body 171.
The first rotating body 171 is rotatably supported by the shaft
member 73. The support shaft 73b of the shaft member 73 is inserted
into the insertion hole 171c of the first rotating body 171. With
this configuration, the first rotating body 171 is rotatable around
a center axis C3.
The first rotating body 171 and the shaft member 73 are provided on
the inner peripheral surface 24b side of the intermediate transfer
belt 24.
At least a portion of the first region 171d1 of the outer
peripheral surface 171d of the first rotating body 171 faces the
inner side surface 61a (left side surface in FIG. 5) which is the
surface of the positioning projection 61 on the first direction D1
side. The first region 171d1 is preferably separated from the inner
side surface 61a.
At least a portion of the second region 171d2 of the outer
peripheral surface 171d of the first rotating body 171 faces the
inner peripheral surface 24b. The second region 171d2 is preferably
separated from the inner peripheral surface 24b. The center axis C3
of the first rotating body 171 is inclined in a direction away from
the intermediate transfer belt 24 as the center axis C3 goes in the
second direction D2.
When the intermediate transfer belt 24 and the positioning
projection 61 move in the first direction D1, the inner side
surface 61a of the positioning projection 61 abuts on the first
region 171d1 of the outer peripheral surface 171d of the first
rotating body 171. For that reason, the movement of the
intermediate transfer belt 24 in the first direction D1 is
regulated. With this configuration, the deviation of the
intermediate transfer belt 24 can be suppressed. Therefore, the
reliability of the positioning of the intermediate transfer belt 24
can be improved.
When the positioning projection 61 abuts on the first region 171d1
of the outer peripheral surface 171d of the first rotating body
171, the first rotating body 171 rotates around the center axis C3
as the intermediate transfer belt 24 and the positioning projection
61 run. For that reason, the frictional resistance between the
positioning projection 61 and the first rotating body 171 can be
suppressed.
When the intermediate transfer belt 24 moves in the direction
(downward in FIG. 5) approaching the center axis C (see FIG. 3),
the inner peripheral surface 24b abuts on the second region 171d2
of the outer peripheral surface 171d of the first rotating body
171. For that reason, the movement of the intermediate transfer
belt 24 in the direction approaching the center axis C (see FIG. 3)
is regulated.
When the intermediate transfer belt 24 abuts on the second region
171d2 of the outer peripheral surface 171d of the first rotating
body 171, the first rotating body 171 rotates around the center
axis C3 as the intermediate transfer belt 24 and the positioning
projection 61 run. For that reason, the frictional resistance
between the intermediate transfer belt 24 and the first rotating
body 171 can be suppressed.
The second rotating body 172 includes a columnar main portion 172a,
and a flange part 172b provided at one end (end in the second
direction D2) in the axial direction of the columnar main portion
172a. A reference symbol C4 is the center axis (rotating body axis)
of the second rotating body 172. At the center of the second
rotating body 172, an insertion hole 172c penetrating the second
rotating body 172 in the axial direction is formed.
The second rotating body 172 is rotatably supported by the shaft
member 74. The support shaft 74b of the shaft member 74 is inserted
into the insertion hole 172c of the second rotating body 172. With
this configuration, the second rotating body 172 is rotatable
around a center axis C4. The center axis C4 of the second rotating
body 172 is parallel to the center axis C (roller axis) (see FIG.
3).
The second rotating body 172 and the shaft member 74 are provided
on the outer peripheral surface 24c side of the intermediate
transfer belt 24. The second rotating body 172 is installed such
that at least a portion of an outer peripheral surface 172d of the
columnar main portion 172a faces the outer peripheral surface 24c
of the intermediate transfer belt 24. The outer peripheral surface
172d of the second rotating body 172 is preferably separated from
the outer peripheral surface 24c.
At least a portion of the outer peripheral surface 172d of the
second rotating body 172 faces the outer peripheral surface 61c
(upper surface in FIG. 5) of the positioning projection 61 via the
intermediate transfer belt 24.
The flange part 172b is formed to protrude radially outward of the
second rotating body 172 with respect to the columnar main portion
172a. At least a portion of an inner side surface 172b1 of the
flange part 172b on the first direction D1 side faces an end
surface 24a1 of the side edge 24a of the intermediate transfer belt
24 on the second direction D2 side. The inner side surface 172b1 is
preferably separated from the end surface 24a1.
A portion of the inner side surface 172b1 may face an outer side
surface 61b (right side surface in FIG. 5) which is the surface of
the positioning projection 61 on the second direction D2 side. The
inner side surface 172b1 is preferably separated from the outer
side surface 61b.
When the intermediate transfer belt 24 and the positioning
projection 61 move in a direction (upward in FIG. 5) away from the
center axis C (roller axis) (see FIG. 3), the outer peripheral
surface 24c of the intermediate transfer belt 24 abuts on the outer
peripheral surface 172d of the second rotating body 172. For that
reason, the outward movement (upward movement in FIG. 5) of the
intermediate transfer belt 24 is regulated. With this
configuration, it is possible to regulate that the positioning
projection 61 comes off the position where the positioning
projection 61 can be made to abut on the first rotating body 171.
Therefore, the reliability of the positioning of the intermediate
transfer belt 24 can be improved.
When the intermediate transfer belt 24 abuts on the outer
peripheral surface 172d of the second rotating body 172, the second
rotating body 172 rotates around the center axis C4 as the
intermediate transfer belt 24 runs. For that reason, the frictional
resistance between the intermediate transfer belt 24 and the second
rotating body 172 can be suppressed.
The flange part 172b can regulate the intermediate transfer belt 24
from moving to the second direction D2 side.
Next, a belt positioning structure 30C which is a third example of
the belt positioning structure 30 will be described with reference
to FIG. 6. The same components as those of the belt positioning
structures 30A and 30B illustrated in FIGS. 4 and 5 are denoted by
the same reference numerals, and description thereof is
omitted.
As illustrated in FIG. 6, the belt positioning structure 30C is
different from the belt positioning structure 30A illustrated in
FIG. 4 in that a first rotating body 271 and a second rotating body
272 are used instead of the first rotating body 71 and the second
rotating body 72.
An outer peripheral surface 271d of the first rotating body 271
includes a first region 271d1 and a second region 271d2. The first
region 271d1 is a tapered region in which the outer diameter
gradually decreases from a position close to a first end 271a
toward the center in the axial direction. The second region 271d2
is a tapered region in which the outer diameter gradually decreases
from a position close to a second end 271b toward the center in the
axial direction.
An insertion hole 271c penetrating in the axial direction is formed
in the first rotating body 271.
The first rotating body 271 is rotatably supported by the shaft
member 73. The support shaft 73b of the shaft member 73 is inserted
into the insertion hole 271c of the first rotating body 271. With
this configuration, the first rotating body 271 is rotatable around
a center axis C5.
The first rotating body 271 and the shaft member 73 are provided on
the inner peripheral surface 24b side of the intermediate transfer
belt 24.
At least a portion of the first region 271d1 of the outer
peripheral surface 271d of the first rotating body 271 faces the
inner side surface 61a (left side surface in FIG. 6) which is the
surface of the positioning projection 61 on the first direction D1
side. The first region 271d1 is preferably separated from the inner
side surface 61a.
At least a portion of the second region 271d2 of the outer
peripheral surface 271d of the first rotating body 271 faces the
inner peripheral surface 61d (lower surface in FIG. 6) of the
positioning projection 61. The second region 271d2 is preferably
separated from the inner peripheral surface 61d. The center axis C5
of the first rotating body 271 is inclined in a direction away from
the intermediate transfer belt 24 as the center axis C5 goes in the
second direction D2.
When the intermediate transfer belt 24 and the positioning
projection 61 move in the first direction D1, the inner side
surface 61a of the positioning projection 61 abuts on the first
region 271d1 of the outer peripheral surface 271d of the first
rotating body 271. For that reason, the movement of the
intermediate transfer belt 24 in the first direction D1 is
regulated. With this configuration, the deviation of the
intermediate transfer belt 24 can be suppressed. Therefore, the
reliability of the positioning of the intermediate transfer belt 24
can be improved.
When the positioning projection 61 abuts on the first region 271d1
of the outer peripheral surface 271d of the first rotating body
271, the first rotating body 271 rotates around the center axis C5
as the intermediate transfer belt 24 and the positioning projection
61 run. For that reason, the frictional resistance between the
positioning projection 61 and the first rotating body 271 can be
suppressed.
When the intermediate transfer belt 24 and the positioning
projection 61 move in a direction approaching the center axis C
(see FIG. 3), the inner peripheral surface 61d of the positioning
projection 61 abuts on the second region 271d2 of the outer
peripheral surface 271d of the first rotating body 271. For that
reason, the movement of the intermediate transfer belt 24 in the
direction approaching the center axis C (see FIG. 3) is
regulated.
When the positioning projection 61 abuts on the second region 271d2
of the outer peripheral surface 271d of the first rotating body
271, the first rotating body 271 rotates around the center axis C5
as the intermediate transfer belt 24 and the positioning projection
61 run. For that reason, the frictional resistance between the
positioning projection 61 and the first rotating body 271 can be
suppressed.
An outer peripheral surface 272d of the second rotating body 272
includes a third region 272d1 and a fourth region 272d2. The third
region 272d1 is a tapered region in which the outer diameter
gradually decreases from a position close to a first end 272a
toward the center in the axial direction. The fourth region 272d2
is a tapered region in which the outer diameter gradually decreases
from a position close to a second end 272b toward the center in the
axial direction.
An insertion hole 272c penetrating in the axial direction is formed
in the second rotating body 272.
The second rotating body 272 is rotatably supported by the shaft
member 74. The support shaft 74b of the shaft member 74 is inserted
into the insertion hole 272c of the second rotating body 272. With
this configuration, the second rotating body 272 is rotatable
around a center axis C6.
At least a portion of the third region 272d1 of the outer
peripheral surface 272d of the second rotating body 272 faces the
end surface 24a1 of the side edge 24a of the intermediate transfer
belt 24 on the second direction D2 side. The third region 272d1 is
preferably separated from the end face 24a1.
A portion of the third region 272d1 may face the outer side surface
61b (right side surface in FIG. 6) which is the surface of the
positioning projection 61 on the second direction D2 side. The
third region 272d1 is preferably separated from the outer side
surface 61b.
At least a portion of the fourth region 272d2 of the outer
peripheral surface 272d of the second rotating body 272 faces the
outer peripheral surface 24c of the intermediate transfer belt 24.
The fourth region 272d2 of the second rotating body 272 is
preferably separated from the outer peripheral surface 24c.
At least a portion of the fourth region 272d2 of the second
rotating body 272 faces the outer peripheral surface 61c (upper
surface in FIG. 6) of the positioning projection 61 via the
intermediate transfer belt 24.
The center axis C6 of the second rotating body 272 is parallel to
the center axis C5 of the first rotating body 271.
When the intermediate transfer belt 24 and the positioning
projection 61 move in a direction (upward in FIG. 6) away from the
center axis C (roller axis) (see FIG. 3), the outer peripheral
surface 24c of the intermediate transfer belt 24 abuts on the
fourth region 272d2 of the outer peripheral surface 272d of the
second rotating body 272. For that reason, the outward movement
(upward movement in FIG. 6) of the intermediate transfer belt 24 is
regulated. With this configuration, it is possible to regulate that
the positioning projection 61 comes off the position where the
positioning projection 61 can be made to abut on the first rotating
body 271. Therefore, the reliability of the positioning of the
intermediate transfer belt 24 can be improved.
When the intermediate transfer belt 24 abuts on the outer
peripheral surface 272d of the second rotating body 272, the second
rotating body 272 rotates around the center axis C6 as the
intermediate transfer belt 24 runs. For that reason, the frictional
resistance between the intermediate transfer belt 24 and the second
rotating body 272 can be suppressed.
The third region 272d1 can regulate the intermediate transfer belt
24 from moving to the second direction D2 side.
Next, a belt positioning structure 30d which is a fourth example of
the belt positioning structure 30 will be described with reference
to FIG. 7. The same components as those of the belt positioning
structures 30A, 30B, and 30C illustrated in FIGS. 4 to 6 are
denoted by the same reference numerals, and description thereof is
omitted.
As illustrated in FIG. 7, the belt positioning structure 30D is
different from the belt positioning structure 30C illustrated in
FIG. 6 in that a first urging mechanism 81 and a second urging
mechanism 82 are provided.
The first urging mechanism 81 includes a first shaft holding
portion 83 and a first urging body 84. The first shaft holding
portion 83 includes a substrate 83a and a pair of side plates 83b,
83b. The side plate portions 83b, 83b hold a shaft member 273 that
rotatably supports the first rotating body 271. The first urging
body 84 is connected to the substrate 83a. The first urging body 84
is, for example, an elastic member such as a coil spring. The first
urging body 84 urges the first rotating body 271 in a direction
approaching the positioning projection 61 via the first shaft
holding portion 83.
The second urging mechanism 82 includes a second shaft holding
portion 85 and a second urging body 86. The second shaft holding
portion 85 includes a substrate 85a and a pair of side plates 85b,
85b. The side plates 85b, 85b hold a shaft member 274 that
rotatably supports the second rotating body 272. The second urging
body 86 is connected to the substrate 85a. The second urging body
86 is, for example, an elastic member such as a coil spring. The
second urging body 86 urges the second rotating body 272 in a
direction approaching the positioning projection 61 via the second
shaft holding portion 85.
In the belt positioning structure 30D, the first rotating body 271
and the second rotating body 272 are urged toward the positioning
projection 61 by the first urging mechanism 81 and the second
urging mechanism 82, and thus the positioning projection 61 can be
stably positioned. Therefore, the reliability of the positioning of
the intermediate transfer belt 24 can be improved.
In the belt positioning structure 30D, although the first rotating
body 271 is provided with the first urging mechanism 81 and the
second rotating body 272 is provided with the second urging
mechanism 82, the urging mechanism may be provided on only one of
the first rotating body and the second rotating body. That is, the
urging mechanism may be provided on at least one of the first
rotating body and the second rotating body.
Next, examples of installation positions of the first rotating body
and the second rotating body will be described with reference to
FIG. 8.
FIG. 8 illustrates a belt positioning structure including a driving
roller 132 (belt roller), a driven roller 133 (belt roller), and
the intermediate transfer belt 24. Units 134 including the first
rotating body and the second rotating body are provided on the
upstream side of the driving roller 132 in a belt running direction
and on the upstream side of the driven roller 133 in the belt
running direction, respectively.
Since the units 134 are respectively provided on the upstream sides
of the rollers 132 and 133, the positioning projection 61 can be
stably positioned. Therefore, the reliability of the positioning of
the intermediate transfer belt 24 can be improved.
As illustrated in FIG. 9, the units 134 including the first
rotating body and the second rotating body can be provided at both
ends in a width direction of the intermediate transfer belt 24,
respectively. With this configuration, the intermediate transfer
belt 24 is positioned at both ends in the width direction (roller
axis direction). As a result, the deviation of the intermediate
transfer belt 24 in both directions in the roller axis direction is
suppressed. Therefore, the reliability of the positioning of the
intermediate transfer belt 24 can be improved.
Although the first rotating body and the second rotating body are
included in the belt positioning structure 30, the belt positioning
structure according to the embodiment may be configured without the
second rotating body. In this case, instead of the second rotating
body, a non-rotating type regulating member that regulates movement
of the belt in the direction away from the roller axis may be
provided.
Although the positioning projection 61 is formed continuously in
the length direction of the intermediate transfer belt 24 in the
belt positioning structure 30, the configuration of the positioning
projection is not particularly limited. For example, the
positioning projections may be formed discontinuously in the length
direction of the intermediate transfer belt. Specifically, the
positioning projection may be a projection formed intermittently
along the length direction of the intermediate transfer belt.
The image forming apparatus may be a monochrome image forming
apparatus. The number of image forming parts is not limited. The
image forming apparatus may include a plurality of printer
units.
The belt positioning structure according to the present embodiment
may be applied to a transfer belt used in a direct transfer type
printer unit.
According to at least one embodiment described above, by providing
the first rotating body that regulates the projection from moving
in the first direction approaching the belt roller along the roller
axis, the reliability of belt positioning can be improved.
While certain embodiments have been described, these embodiments
have been presented by way of example only, and are not intended to
limit the scope of the inventions. Indeed, the novel embodiments
described herein may be embodied in a variety of other forms;
furthermore, various omissions, substitutions and changes in the
form of the embodiments described herein may be made without
departing from the spirit of the inventions. The accompanying
claims and their equivalents are intended to cover such forms or
modifications as would fall within the scope and spirit of the
inventions.
* * * * *